1. Field of the Invention
The present invention generally concerns improvements to stakes used in construction to temporarily hold things, such as construction forms, in position upon the surface of the earth. The stakes of the present invention will be seen to be particularly, although not exclusively, useful in the practice of a patented method of constructing a monolithic in-situ concrete slab foundation and in related concrete work.
The construction stakes of the present invention are particularly useful as part of a construction form system, and in a method of making a slab on grade foundation.
2. Description of the Prior Art
While much prior art can be found in the field of slab foundations and related concrete work, the commercial success of contemporary proprietary systems which form a concrete-slab-on grade is limited. The primary reasons for this are that the proprietary systems tend to be expensive, contrived, and inflexible. Furthermore, forming a concrete slab on a prepared building pad is not a significant engineering feat, and so is generally endeavored with simple boards and stakes.
The board and stake concept offers design flexibility, but it does have significant drawbacks. These drawbacks include: wasted labor to define and check geometry, poor accuracy of surfaces and embedded hardware, difficulty in adjusting form locations after stakes are set, and inconsistent repeatability for multiple units. Back injury, caused by pulling a conventional stake out of the ground, is a common complaint in the foundation business. Poor foundation accuracy is always a concern, and it has a more consequential negative affect on the framing process for a structure of light gage metal members. This is because the framing assemblages of these members tolerate little dimensional error at the points of support.
Established proprietary concrete forming systems include such ones as xe2x80x98Metaformxe2x80x99, which are of folded sheet metal. Lengths are generally in 10xe2x80x2 increments, which is the length of the brake that folds the sheet metal. For a long run of perimeter form this results in frequent potential segmental kinks. Conforming to custom dimension and design requires the cutting up of relatively expensive lengths of form. Stakes must be placed only at specific holder locations provided on the forms, and no subsequent relative horizontal adjustment is possible. If a rock or obstruction happens to be at one of these specific locations, then one must compromise either form location or stake support.
Solutions addressing the need to adjust forms relative to stakes include the system disclosed in Canadian patent 1,145,179 by Breitenbach, issued Apr. 26, 1983. This apparatus allows adjustment of form location subsequent to setting of stakes, by a system of supporting yokes consisting of bars, sleeves, and brackets. This type of a solution involves one or a pair of sets of moving parts for each direction of adjustment. Each supporting assemblage is subject to unwanted lateral movement due to the fact that the each of the supporting stake pairs are required to be essentially parallel for vertical adjustment of the yoke, which attaches to them above the forms. Stakes in loose soils simply do not hold up to this kind of side cantilever loading. Even bending of the stakes can be enough of a problem, given the relatively high point of attachment. Each of these assemblages is heavy, clumsy, relatively expensive, and an obstruction to the concrete work, especially for slab-on-grade foundations. There are too many parts to buy, clean, and maintain.
A somewhat simpler proprietary forming method offers subsequent adjustment in the vertical direction only. This is disclosed in U.S. Pat. No. 3,397,494, Waring, issued Aug. 20, 1968. With this system, vertical support to a proprietary perimeter member is provided with rods having machine thread. These rods thread into bearing pads that sit upon the earth, and then support the special cast in place perimeter member directly. No allowance is provided for rod location. It must be directly at a hole in the member, regardless of what local anomaly or rock may be at the ground below that point. The rod supports offer little resistance to uplift from the buoyant forces of concrete placement, because they do not have threads capable of threading into earth, and so are not used in that manner. This support offers essentially no lateral force resistance. In fact, the system requires a redundant conventional perimeter form board with conventional stakes, et cetera, for structural stability. The main purpose of the present invention is to provide placement of a cast in-situ foundation perimeter for a proprietary wall system which requires a special recessed ledge.
For slab-on-grade foundations, most contractors prefer to continue to form with simple boards and stakes, in spite of the drawbacks, because they do not impose a lot of contrivance, have a low initial cost, and provide flexibility in geometry. Those in the trades have grown to accept the challenges of building foundations with a most primitive technology. It is generally understood that foundation construction includes performing redundant efforts at determining geometry, having a difficult time making geometrical adjustments, and then getting complaints about accuracy from the people building the structure atop anyway. In truth, all of these problems really can be solved without forcing a lot of limitations and contraptions upon the foundation builder, as the following discussion will illustrate.
The objects and advantages of the present invention will shortly be seen to bee as follows.
In order to evaluate a new foundation construction practice, it is sensible to first examine some contemporary needs of the industry.
Tract home builders most often build slab-on-grade foundations. Normally, a building pad is created for each unit. This pad is typically graded so as to completely facilitate slab-on-grade foundation construction. Identical unit footprints, and mirrored versions, are repeated often. The foundation forming method should effectively address this circumstance.
Homes built today tend to have more seismic hardware anchored in the foundation than earlier homes did. Increasingly, post-tension slab-on-grade foundations are being built in order to achieve economy at sites having expansive soil conditions. All of the post-tension anchors must be located correctly along the perimeter form, and in conjunction with the conventional hardware embedments. In general, more connections located in a tighter space demands more accuracy of the foundation forming method which locates these items. Additionally, the task of physically locating an element of hardware is performed very often. So, the task must be made to be as easy and repeatable as possible.
A growing number homes are being framed with members of cold-formed light-gage steel. The framing of these homes requires greater accuracy than most foundation contractors will deliver, particularly for the cost effective xe2x80x98panelizedxe2x80x99 structures (the metal stud walls are framed in a shop and erected at site). For the increasingly common xe2x80x98panelizedxe2x80x99 structure, a very accurate foundation, to the last hardware embedment, is required for cost effective construction. For repeat units of xe2x80x98panelizedxe2x80x99 homes, the accuracy must be such that entire buildings and foundations be considered as interchangeable parts, if true production building is to occur.
An important component of foundation accuracy is easy adjustment of location of foundation forms, so that needed adjustments are made rather than ignored. For custom built structures, provision for easy adjustment of foundation forms is significant. This is because, compared to repetitive construction, relatively far more labor tends to be expended on the custom geometry definition. So, the ability to have adjustment after forms are initially set up, provides a big labor savings for even one unit. It is best if all the foundation form support locations can be adjusted simultaneously. This way an entire lightweight forming unit, which is internally collocating, can be assembled whole, floating on supports, before being committed to the exact permanent placement.
Most contemporary post-tension slab-on-grade foundation construction is built on a flat-graded earth pad without trenches. This increasingly popular method requires no lay out of trenches, so a foundation forming method which does not require the lay out of any geometry at all, can provide significant labor-saving benefit to the foundation construction process.
The present invention provides the fastest means possible of constructing a concrete slab foundation. The process is more convenient and less injurious than conventional methods. The investment is less and the utility more diverse than with other proprietary methods. The results are more reliable and accurate. Components of the present invention offer novel utility independently, and with elements of co-pending patent applications, they offer substantial benefit for other types of foundations.
The present invention utilizes the increasingly available light-gage roll-formed steel members as concrete forms. They are low cost, light-weight, and are supplied in any desired lengths. These standardized xe2x80x9cCxe2x80x9d shaped sections are supported by exceptionally simple components which allow subsequent adjustment of forms relative to stakes, in all three orthogonal directions.
Other elements of the present invention combine with the form members to create a collocating-upon-assembly forming unit for an entire slab foundation. This forming unit may be assembled while floating on supports, and then adjusted into place. It can be built to be light-weight enough to allow a crew to carry it whole from unit to unit, as if it were a large cookie cutter.
With the present invention, adjustments to form locations are facilitated by the use of coarsely threaded rods which offer support directly. This is because the same adjustment rods which connect to form components, also thread directly into the earth. Threading into earth improves resistance to buoyant forces from concrete placement, and thus facilitates use of light-weight forms. The threaded stakes may also be angled outward so as to buttress the forms directly. They are much easier to get into and back out of the ground than conventional stakes are. Threaded stakes offer significant improvements to the construction of most any type of in-situ concrete foundation.
The present invention requires less labor than any other method to build a concrete slab foundation. It will please any builder with the inherent, repeatable accuracy. Elements of the present invention provide labor-saving and quality-enhancing utility for most kinds of foundations.
The present invention contemplates a reusable steel threaded stakes that are (i) easily driven into, and easily extracted from, even hard earth by use of lever tools including power tools, and, once situated, are (ii) versatile to interact with each other, to align things such as construction forms and, uncommonly, in combination to support a construction form level and true above the surface of the earth.
The threaded construction stakes of the present invention, although well suited and superior for general use in construction, are particularly efficacious of use with the construction form system, and method, for easily and efficiently making a slab on grade foundation upon the surface of the earth that is the subject of the related predecessor U.S. Pat. No. 5,830,378. In the system and method of that invention the construction stakes support a fast and easy, repetitive, setup of a construction form supported level and true above the surface of the earth. The stakes are interactive with a quick-acting device for connecting and holding the construction form to the stakes precisely and accurately at any arbitrary position.
The present invention is embodied in a stake generally suitable for use in construction of buildings upon the face of the earth. The preferred embodiment of a construction stake of the present invention consists of an elongate threaded metal member having (i) a length between 0.45 meter and 1.8 meter, (ii) a tapered (pointed) first end region that is suitable to penetrate the earth under force of screwing the member into the earth, and (iii) a second end region in the shape of a regular prism.
The prism-shaped second end region is suitable to be engaged and to be rotated, turning the entire elongate threaded member by a rotating tool which may be manual but which is most commonly a power tool, normally of the pneumatic impact wrench or electric drill type. Particularly by use of a power torquing tool the threaded stakes may be easily driven and strongly set into even the hardest earth. (The stakes are not for use in solid rock, but may easily bypass such rocks as are commonly found even in rocky soils.)
In one, less preferred, embodiment the second end region has a maximum diameter that is everywhere effectively less than a root diameter of the externally threaded middle region. The second end region typically has a hexagonal cross section, and is engagable by a standard socket of a torquing tool for screwing the member into, and out of, the earth.
In its preferred embodiment the second end region is comprised of two nuts that (i) thread the elongate threaded member, the treads of which are continued all the way to the rod""s second end, and (ii) are subsequently jammed together at any convenient displacement within the second end region from the second end, at which time neither nut will turn unless forcibly disengaged from the other. In accordance that the threads to the rod body, next discussed, preferably have a particular formxe2x80x94coil threadsxe2x80x94and are thus preferably of a high pitch, the two nuts are most commonly not everyday common machine nuts. Their principle of operation is, however, the same as any nut. Each nut threads quite easily upon even a dirty or corroded rod, including by simple force of the hand and fingers, until, at the desired position, the end-most is modestly jammed, or locked, against an inner nut. At this time a torquing tool mounting a deep wall socket is fit around the upper nut only, and, the inner nut not turning, will suffice to rotate the rod, threading it into the earth. The nuts normally become jammed, or locked, together so tightly that the rod may later be unscrewed from the earth by reverse torque as is applied to the outer nut only. A heavy wrench, or even a pipe wrench, may alternatively be used to engage either nut both so as to turn the rod in one direction so as to screw it into the earth, or in the other direction so as to unscrew it from the earth. However, if the nuts work apart, then the torque to unscrew the rod from the earth may be applied to the inner nut by a wrench. The nuts can of course be separated by the simple expedient of torquing each in an opposite direction, normally by use of two wrenches, or one wrench and the power torquing tool.
The thread of the middle region is preferably both (i) deeply cut, having at a ratio of root diameter to outside diameter of typically less than 0.80, and (ii) steeply inclined, the threads having an incline of about 1 in 9.4. The steepest incline that will permit the nuts to remain tight is optimal for driving the stakes into dirt, and incline is preferably at least 1 in 20. If the less preferred embodiment of the second end region in the shape of a prism of diameter everywhere effectively less than the root diameter of the externally threaded middle region is employed, then a threaded nut may be passed over the second end region in order to threadingly engage the middle region. In other words, nuts can be used with and on the central region of the rod memberxe2x80x94which is always threadedxe2x80x94regardless that the second end region of the rod should, in a less preferred embodiment, not be threaded.
The stake is preferably made from a 0.6 meter to 1.8 meter (two foot to six foot) length of steel rod having a low root-to-major-diameter ratio, normally less than 0.5. Standard steel coil rod having an approximate diameter of 12 millimeters and approximately 6 threads each 25.4 millimeters is most suitable. The stake""s first end region is preferably tapered to a point over at least 1.9 centimeters (xc2xe inches) of length.
In the preferred embodiment, the stake has an upper end enabling a torsional force to be applied via a pair of mutually locked hex nuts, in lieu of a prismatically shaped end. With this configuration, the top of the stake is a simple cut end, which can be de-burred as required. In this embodiment the stake has and presents steeply inclined threads not only in its entire middle region between the first and the second end regions, but also contiguously from the middle region through the second end region all the way to the second end.
In a less preferred embodiment the second end, top, region of the stake is preferably formed to a regular prism over at least 1.3 centimeters (xc2xd inch) of length. In this case the threads at the other, first, end region of the stake, and in the middle region, need only extend so far as the stake is likely to be driven into the ground. Normally, however, for ease of manufacture the threads extend the full length of the stake all the way to the prismatic second end, top, region.
If the second end region in the shape of the regular prism, preferably the hexagonal prism, then it is preferably so formed by milling over at least 2.54 centimeters (1 inch) of length. The head may alternatively be formed by forging, again preferably in the shape of a regular prism. The head in the shape of a regular prism facilitates that a rotating tool engaging this second end head region may impart considerable torque to rotating the stake without damage to, or excessive wearing of, the stake.
Of course, the same is true of the preferred second end region jammed nuts. If, due to excessive torque, one or both of these nuts becomes worn or even split, substA Construction Form System
The threaded stakes of the present invention are particularly efficacious of use in construction form system. The construction form system is based on a form that is capable of being assembled, aligned, trued and thereafter moved intact over and upon the earth. The construction form has and presents (i) a substantially planar face to its interior and (ii) a substantially contiguous peripheral xe2x80x9cCxe2x80x9d-channel to its exterior.
In accordance with a related invention, a collocating sub-system is used to conveniently, easily, quickly, accurately and precisely spatially locate and hold this construction form above the earth. The sub-system is based on several cooperatively interactive parts.
A number of bent-planar-elements twist slightly about an imaginary horizontal axis so as to engage and hold the construction form at its peripheral exterior xe2x80x9cCxe2x80x9d channel. These bent-planar-elements are preferably in the substantial form of bent plane having (i) a length, and (ii) a cross section, orthogonal to an axis of the length, that is topologically equivalent to a xe2x80x9cUxe2x80x9d with a substantially central trough and two flanges. Each of the two flanges has at its furthest extent a feature that is complimentary to fit within, and to engage, the xe2x80x9cCxe2x80x9d-channel of the construction form. When so engaged the bent-planar-element extend across the width of the xe2x80x9cCxe2x80x9d-channel, and across the width of the construction form of which the xe2x80x9cCxe2x80x9d-channel is a part.
A large number of elongate metal stakes of the present inventionxe2x80x94tapered (typically to a sharp point) on one end while presenting a feature for coupling rotational forces on the other end while threaded in the middlexe2x80x94are conveniently locatedxe2x80x94normally by being screwed into the earth by hand-held power torque wrenchxe2x80x94at the external periphery of the sited construction form. A first group of the stakes are each so screwed into the earth roughly vertically through an aperture formed by the xe2x80x9cUxe2x80x9d cross-section of a bent planar element and the exterior of the construction form engaged (at its xe2x80x9cCxe2x80x9d channel) by this bent planar element. Meanwhile, preferably yet another, second, group of the stakes are screwed into the earth at an incline so as to approximately intersect the approximately vertical first group of stakes at spatial regions above the earth, and above the bent planar elements. The stakes are typically cut and formed in 0.6 meter to 1.8 meter lengths from steel coil rod.
A number of first assemblies both slip and thread the substantially vertical stakes of the first group so as to ultimately be held by threaded engagement with these stakes at selected heights that are suitable to collocate and to hold the bent planar elements, and thus also the construction form that the bent planar elements engage, level above the earth. These first assemblies preferably consist of a number of nuts and open-channeled xe2x80x9chairpinxe2x80x9d bars. The nuts either slide over, or thread, the top of the featured end regions of the first group of stakes, and thread a threaded middle region of the stakes. The open-channeled xe2x80x9chairpinxe2x80x9d bars slip over and along the stakes until coming to rest against a nut. The bars serve to increase the effective external diameter of the nut.
Because the bent-planar-elements are, as previously stated, preferably in the substantial form of bent plane having (i) a length, and (ii) a cross section, orthogonal to an axis of the length, that is topologically equivalent to a xe2x80x9cUxe2x80x9d with a substantially central trough and two flanges, each of the two flanges serves, in conjunction with the engaged xe2x80x9cCxe2x80x9d-channel of the construction form, to present an aperture. A vertical stake of the first group is passed through this aperture and is threaded into the earth. Each of the bent-planar-elements is stopped and held by an associated one of the first assemblies, each at a position determined by this first assembly and its associated stake.
By this arrangement of parts, a vertical stakes is passed through a trough of a bent-planar-element. The bent-planar-element is subsequently stopped to the stake by the open-channeled bar and the nut. Thus stopped the bent-planar element serves to engage, and to hold, the foundation form at a localized region. The collective bent-planar elements, first assemblies and vertical stakes thus serve to support the foundation form level above the earth.
Remaining sub-system parts serve to accurately precisely adjust the supported foundation in direction (i.e., in angle of rotation in the level plane). A number of second assemblies slip and thread both the substantially vertical stakes and the associated inclined stakes so as to ultimately be held to, and between, these stakes by threaded engagement with both. These second assemblies are adjustable so as to move the upwards extension of the vertical stakes relative to the inclined stakes, and relative to the earth, so that the level construction form is adjusted in direction. Notably, the level support of the construction form above the earth by and on the bent-planar-elements, the first assemblies, and the vertical stakes both accommodates and permits this adjustment.
Opposite corners of the construction form may be connected with and by adjustable squaring wires in order to promote correct and square location of the sides of the construction form.
Accordingly, the construction form is conveniently, easily, quickly, accurately, and precisely spatially located and held above the earth. When a pourable construction material is poured into the construction form a slab on grade foundation is created. Each of the construction form, the vertical and inclined stakes, the bent-planar-elements, and the first and second assemblies may all be removed from the foundation of hardened pourable construction material, re-sited, and reused.
The threaded construction stakes of the present invention support the method of making a slab on grade foundation that is the subject of U.S. Pat. No. 5,830,378.
In the preferred method a foundation form is first assembled upon the surface of the earth. The form engages at and around its periphery a number of xe2x80x9cUxe2x80x9d-shaped bent-planar members, the xe2x80x9cUxe2x80x9d of the member and the exterior surface of the form jointly creating and presenting a vertically oriented elongate aperture.
A number of first threaded stakes in accordance with the present invention are then screwed substantially vertically into the earth though the vertically oriented elongate apertures as are situated periodically at convenient intervals around a periphery of the foundation form. Meanwhile, a number of second threaded stakes in accordance with the present invention are screwed into the earth so as to proximately spatially intersect the first threaded stakes at regions above the earth.
A first assembly is adjustably located upon each first threaded, substantially-vertical, stake by, ultimately, a threaded affixation to the threads of the stake. Each first assembly serves to support a corresponding xe2x80x9cUxe2x80x9d-shaped bent-planar member, and through this corresponding member, the construction form, upon a first threaded stake. Each first assembly and associated bent planar member are thus used to temporarily locally join a first stake to the external circumference of the foundation form. The collective xe2x80x9cUxe2x80x9d-shaped bent-planar members and first assemblies collectively temporarily join the entire foundation form to the first stakes, temporarily supporting the foundation form level above the surface of the earth.
A second assembly located on and between both of each first threaded stake and its associated second threaded stake is used to temporarily join these stakes at a region above the surface of the earth. The collective action of the collective second assemblies collectively serves to directionally align the temporarily suspended foundation form to the surface of the earth.
Finally, a pourable construction material is poured into the foundation form so held and supported and so directionally aligned in order to make a slab on grade foundation.
In still another of its aspects the threaded construction stakes of the present invention are interactive with a device serving to connect the stakes to a substantially horizontal elongate construction form having an elongate planar face and an opposite elongate xe2x80x9cCxe2x80x9d-channel with lips.
The device includes a clip element in the substantial form of bent plane having a length and a cross section, orthogonal to an axis of the length, that is topologically equivalent to a xe2x80x9cUxe2x80x9d with a substantially central trough and two flanges. Each of the two flanges has at its furthest extent a feature that is complimentary to fit within, and to engage, the xe2x80x9cCxe2x80x9d-channel of the construction form. The clip element is slightly rotated in an imaginary horizontal axis so that the two flanges of its trough engage the xe2x80x9cCxe2x80x9d-channel of the construction form. When so engaged the clip element extends across the width of the xe2x80x9cCxe2x80x9d-channel, and the construction form of which the xe2x80x9cCxe2x80x9d-channel is a part.
A first nut screws upon the threaded stake. This nut has an external diameter smaller than the trough of the clip element. It may thus be semi-permanently left mounted upon the threaded stake, including during insertion of the threaded stake into and through the xe2x80x9cUxe2x80x9d-channel of the clip element.
A first, bar, element having an open-ended channel is side slipped over the threaded stake. The channel of this first bar element is larger than the diameter of the threaded stake but smaller than the external diameter of the first nut.
According to this arrangement, the first nut abutting the first bar element abutting a first end of the clip element""s trough serves to locate and position this trough, and the clip element, along the substantially vertical threaded stake.
A second nut also screws upon the threaded stake. This nut again has an external diameter smaller than the trough of the clip element.
A second, connective, element having an open-ended channel again side slips over the threaded stake. The channel of this second bar element is larger than the diameter of the threaded stake but smaller than the external diameter of the second nut. The second nut abuts the second bar element which abuts a second end of the clip element""s trough, serving to locate and position this trough, and the clip element, along the substantially vertical threaded stake in a position between the first nut/first bar element and the second nut/second bar element. The first and the second nuts can already be affixed to the threaded rod when the clip element is positioned about the threaded rod or, conversely, the clip element may be positioned about the threaded rod while the first and the second nuts are already affixed.
By this arrangement, the first, bar, element and the second, connective, element can both be side slipped about the threaded rod even when the clip element is already positioned about the threaded rod, and even when the first and the second nuts are already screwed upon the threaded rod.
Collectively in sequence, the clip element is first rotated into position, the threaded stake is then rotationally driven into the ground, then each of the first and the second nuts is screwed into position, and then each of the first and the second bar elements is slipped into position, so as to engage the threaded rod to the construction form.
These and other aspects and attributes of the present invention will become increasingly clear upon reference to the following drawings and accompanying specification.